Neurodegeneration speeds up in presence of vascular risk factors
Vascular risk factors may accelerate neurodegeneration but not the accumulation of amyloid deposits, a recent study has found.
A total of 433 cognitively normal adults (mean age, 68.3±8.5 years; 53 percent female) were enrolled in the study. All participants underwent clinical assessment with the Mini-Mental State Examination (MMSE), as well as a psychometric battery consisting of different cognitive tests. The vascular risk factors included were hypertension, hypercholesterolaemia, diabetes mellitus, depression, smoking and alcohol use habits, and transient ischaemic attacks, among others.
Over a mean clinical follow-up of 5.2±2.7 years, hypercholesterolaemia emerged as the most common vascular risk factor (65 percent). This was followed by hypertension (58 percent) and depression (36 percent). Majority of the participants (72 percent; n=312) had more than one risk factor.
Vascular risk factors appeared to be important in those with preclinical Alzheimer’s disease. Particularly, in participants who were positive for amyloid and tau at baseline, the Framingham Risk Score (FRS) correlated inversely with baseline MMSE scores (p=0.023) and longitudinal decline (p=0.031). Depression, on the other hand, was associated with higher baseline scores (p=0.045).
In the same subgroup of participants, obesity was likewise inversely correlated with baseline p-tau concentrations (p=0.021). In comparison, hypertension as associated with a greater rate of accumulation of t-tau (p=0.002) and p-tau (p<0.001), and a higher FRS was linked to a longitudinal increase in t-tau (p=0.042).
In the overall sample and in any of the subgroups, none of the vascular risk factors assessed yielded significant effects on amyloid accumulation.